second of arc

例句：

1. 1. The engineer calculated the exact length of the second of arc needed for the bridge.
   工程师计算了建造桥梁所需的圆弧的确切长度。
2. 2. The second of arc is the point on the circle where the radius intersects with the line.
   圆弧的第二部分是半径与直线相交的那个点。
3. 3. The construction of the bridge involved the precise measurement of the second of arc.
   建造这座桥需要精确测量圆弧的第二部分。